1. Field of the Invention
The present invention relates generally to a cylinder lock and a key, the lock having lock pins arranged in a cylinder core to read control faces of the key.
2. Description of the Related Art
German Pat. No. 24 11 362, (DE-PS No. 24 11 362) for example, discloses a cylinder lock and a key having auxiliary longitudinal ribs projecting beyond one or more lateral faces of the flat key. The auxiliary longitudinal ribs cooperate with auxiliary lock pins so that the lock pins sense the ribs. When a seam between the cylinder core and the cylinder housing is in alignment, then the cylinder core can be turned to actuate the lock.
A multi-level lock system and method is disclosed in U.S. Pat. No. 4,325,242, including discontinuous rib members at each side of an elongated key. U.S. Pat. No. 4,608,842 also discloses a lock and key system with auxiliary locking ribs and pins.
In EP-PA No. 00 29 498 is disclosed the sensing of the height of a profile or a sub-profile, the height initially being defined by the inserted key. This occurs due to a radially displaceable ball seated in a bore of the key shank.
It is also known that certain materials including metals and metal alloys have what is referred to as memory or thermal recovery or shape memory. In other words, the metals and alloys displaying such characteristic have a first shape at normal ambient temperatures but assume a modified second shape as a function of the energy received in the form of heat, for example. Thus, such metals and alloys discernibly deviate in shape when heated from their shape when cold. For example, a pilotherm, or temperature switch, operating on this principle is known from German utility model No. 79 00 875.
Memory alloys are known from practice and include, for example, NiTi which is used for pressure, tensile, bending or torsion elements.